Very easy problem- i can't seem to get

[Need_help!]

okay so the problem is:

I need to develop a program that determines whether a department store customer has eceeded credit limit on charge account. for each customer, the following facts are available:

- accunt number
Balance at the beg. of the month
total of all items charged by this customer this month
-titak of all credits applied to this customer's account this month
-allowed credit limit

the program should input account number as an Integer, but use Double for the other variables. the program should calculate the new balance (= beggining balance + charges - credit), display the new balance and determine whether is exceeds the customer's credit limit. for customers whose credit limit is exceeded, the program should display the message, " credit limit exceeded. use a sentinal value of -1 for the acount number to terminate repetition.

Okay, here is what i have.. now it runs but i dont have a sentinal value and i dont think i did the problem correctly

Sub Main()
Dim accountNumber As Integer
Dim begBal As Double = 1000
Dim totCharges As Double
Dim newbal As Double
Dim credits As Double = 700

Console.Write("Hello. please enter account number:" & vbCrLf)
accountNumber = Console.ReadLine()
Console.Write(" Beginig balance is: 1000" & vbCrLf)
Console.WriteLine(" Please enter credit amount:" & vbCrLf)
credits = Console.ReadLine()

If credits <= 700 Then ' is charges are smaller than the allowed credit amount then subtract
credits -= 700
Console.WriteLine(" Amount after charge is " & credits)
ElseIf credits > 700 Then ' else if charges exceed the allowed credit amount than do not operate, write "exceed'"
Console.WriteLine(" Credit limit exceeded")
End If

newbal = begBal + totCharges - credits
Console.Write(" new balance is " & newbal & vbCrLf)

CAN ANYONE HELP PLEASE!!??

where does the -1 come in? Don't you need a for loop ?

[Need_help!]

where does the -1 come in? Don't you need a for loop ?

yeah i do need a loop, so it should really be a dountil? but how can i have a dountil if i need an if then type statement right?

You use the -1 as a condition to bail out of the loop i.e

While (input <> -1 ) Then
'promt user for input
total = total + input
End While

Display total

The best thing for you would be to draw a flow chart. It will help you visualise what is going on and help you code a solution.

[Need_help!]

Thats the problem i am not sure really what the program is suppose to be doing, does the user input their account and the credit amount?? im really lost in this easy problem